1. Field
The present specification generally relates to substrates for capturing CO2 from a process gas stream and, more specifically, to sorbent substrates for capturing CO2 from a process gas stream which are formed from co-extruded sorbent filaments comprising a plurality of through-channels and methods for making the same.
2. Technical Background
CO2 is a greenhouse gas that has been linked to global warming CO2 is a bi-product of various industrial processes such as, for example, coal-fired power plants, purification of natural gas, oil recovery systems and the like. From an environmental perspective, carbon trading and future regulations of carbon emissions from flue gasses and other CO2 point sources are economic drivers for improving the efficiency of CO2 capture technologies.
Various technologies are currently being used and/or developed to improve the capture of CO2 from process gas streams. Such technologies include, for example, the liquid amine (MEA or KS-1) process, the chilled ammonia process and gas membranes. While each of these technologies is effective for removing CO2 from a process gas stream, each technology also has drawbacks. For example, the amine process has associated reactor corrosion issues, high capital costs and is considered to be very energy intensive to operate. The chilled ammonia process is still in its early phases of development and the commercial feasibility of the process is not yet known. Some possible challenges with the chilled ammonia process include ammonia volatility and the potential contamination of the ammonia from gaseous contaminants such as SOx and NOx. Various gas membrane technologies are currently employed for the removal of CO2 from process gas streams. However, processes utilizing gas membrane technologies require multiple stages and/or recycling in order to achieve the desired amount of CO2 separation. These multiple stages and/or recycling add significant complexity to the CO2 recovery process as well as increase the energy consumption and cost associated with the process. Gas membrane technologies also typically require high pressures and associated space constraint which makes use of the technology difficult in installations with limited space such as offshore platforms.
Accordingly, a need exists for alternative methods and apparatuses which may be used to recover CO2 from process gas streams.